1. Field of the Invention
The present invention pertains generally to the field of pan heads of the type commonly used with tripod supports in photographic and cinematographic applications, and more particularly is directed to improvements in the hinge assembly for pivotal mounting of the pan head components.
2. State of the Prior Art
The present invention improves over a particular type of pan head which has a table for supporting a camera or other instrument mounted to a tilt arm. More specifically, the table of the prior art pan head assembly was mounted for pivotal movement to a tilt arm by means of a hinge structure comprising a pair of spaced apart hinge portions extending from the table, and a single portion integral to the tilt arm and interposed between the two table lobes. The three hinge portions were secured by means of a pivot tube extending through aligned bores in the three hinge portions. The pivot tube was fixed by a friction fit to the middle lobe, i.e., the lobe integral with the pivot arm while being rotatable within the bores extending through the table lobes on either side of the tilt arm lobe. The portions of the pivot tube extending through the table lobes were slotted in an axial direction at a plurality of circumferentially spaced locations, typically four locations spaced 90 degrees apart, and a tapered nut was fitted into each end of the pivot tube. The tapered nuts weere mounted on a rod which was threaded into one of the nuts and freely rotatable relative to the other nut, but provided with an end knob such that when the rod was rotated by means of the end knob the two tapered nuts were urged together into the opposite ends of the pivot tube causing the tube to enlarge in diameter at each end within the bores in the table lobes. Such enlargement of the pivot tube caused frictional locking between the tube and the table, thus in effect locking the table and the tilt arm against pivotal movement.
In the prior art pan head it was necessary to fix the pivot tube securely to the tilt arm lobe so as to firmly lock together the tilt arm with the table when the ends of the pivot tube were locked within the table lobes. It was found, however, that it was difficult to reliably secure the pivot tube to the tilt arm while using economical assembly methods. It was also found that the number of parts required for such pan head assembly was excessive and resulted in a relatively complex assembly procedure.